Added DataBuffer Encoder/Decoder

This commit adds a DataBuffer Encoder and Decoder, and uses it in
the annotation-based processing model.

Note that these codecs are not used in the functional processing model,
since the BodyInserter/BodyExtractor already have methods for
writing/reading DataBuffers.

Issue: SPR-15148

spring-core/src/main/java/org/springframework/core/codec/DataBufferDecoder.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2002-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.codec;
+
+import java.util.Map;
+
+import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.util.MimeType;
+import org.springframework.util.MimeTypeUtils;
+
+/**
+ * Simple pass-through decoder for {@link DataBuffer}s.
+ * <p><strong>Note</strong> that the "decoded" buffers returned by instances of this class should
+ * be released after usage by calling
+ * {@link org.springframework.core.io.buffer.DataBufferUtils#release(DataBuffer)}.
+ *
+ * @author Arjen Poutsma
+ * @since 5.0
+ */
+public class DataBufferDecoder extends AbstractDecoder<DataBuffer> {
+
+	public DataBufferDecoder() {
+		super(MimeTypeUtils.ALL);
+	}
+
+
+	@Override
+	public boolean canDecode(ResolvableType elementType, MimeType mimeType) {
+		Class<?> clazz = elementType.getRawClass();
+		return (super.canDecode(elementType, mimeType) && DataBuffer.class.isAssignableFrom(clazz));
+	}
+
+	@Override
+	public Flux<DataBuffer> decode(Publisher<DataBuffer> inputStream, ResolvableType elementType,
+			MimeType mimeType, Map<String, Object> hints) {
+		return Flux.from(inputStream);
+	}
+
+}

spring-core/src/main/java/org/springframework/core/codec/DataBufferEncoder.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2002-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.codec;
+
+import java.util.Map;
+
+import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.util.MimeType;
+import org.springframework.util.MimeTypeUtils;
+
+/**
+ * Simple pass-through encoder for {@link DataBuffer}s.
+ *
+ * @author Arjen Poutsma
+ * @since 5.0
+ */
+public class DataBufferEncoder extends AbstractEncoder<DataBuffer> {
+
+	public DataBufferEncoder() {
+		super(MimeTypeUtils.ALL);
+	}
+
+
+	@Override
+	public boolean canEncode(ResolvableType elementType, MimeType mimeType) {
+		Class<?> clazz = elementType.getRawClass();
+		return (super.canEncode(elementType, mimeType) && DataBuffer.class.isAssignableFrom(clazz));
+	}
+
+	@Override
+	public Flux<DataBuffer> encode(Publisher<? extends DataBuffer> inputStream,
+			DataBufferFactory bufferFactory, ResolvableType elementType, MimeType mimeType,
+			Map<String, Object> hints) {
+
+		return Flux.from(inputStream);
+	}
+
+}

spring-core/src/test/java/org/springframework/core/codec/DataBufferDecoderTests.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2002-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.codec;
+
+import java.nio.ByteBuffer;
+import java.util.Collections;
+
+import org.junit.Test;
+import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.io.buffer.AbstractDataBufferAllocatingTestCase;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.util.MimeTypeUtils;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * @author Sebastien Deleuze
+ */
+public class DataBufferDecoderTests extends AbstractDataBufferAllocatingTestCase {
+
+	private final DataBufferDecoder decoder = new DataBufferDecoder();
+
+	@Test
+	public void canDecode() {
+		assertTrue(this.decoder.canDecode(ResolvableType.forClass(DataBuffer.class),
+				MimeTypeUtils.TEXT_PLAIN));
+		assertFalse(this.decoder.canDecode(ResolvableType.forClass(Integer.class),
+				MimeTypeUtils.TEXT_PLAIN));
+		assertTrue(this.decoder.canDecode(ResolvableType.forClass(DataBuffer.class),
+				MimeTypeUtils.APPLICATION_JSON));
+	}
+
+	@Test
+	public void decode() {
+		DataBuffer fooBuffer = stringBuffer("foo");
+		DataBuffer barBuffer = stringBuffer("bar");
+		Flux<DataBuffer> source = Flux.just(fooBuffer, barBuffer);
+		Flux<DataBuffer> output = this.decoder.decode(source,
+				ResolvableType.forClassWithGenerics(Publisher.class, ByteBuffer.class),
+				null, Collections.emptyMap());
+
+		assertSame(source, output);
+	}
+}

spring-core/src/test/java/org/springframework/core/codec/DataBufferEncoderTests.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2002-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.codec;
+
+import java.nio.ByteBuffer;
+import java.util.Collections;
+
+import org.junit.Test;
+import org.reactivestreams.Publisher;
+import reactor.core.publisher.Flux;
+
+import org.springframework.core.ResolvableType;
+import org.springframework.core.io.buffer.AbstractDataBufferAllocatingTestCase;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.util.MimeTypeUtils;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * @author Sebastien Deleuze
+ */
+public class DataBufferEncoderTests extends AbstractDataBufferAllocatingTestCase {
+
+	private final DataBufferEncoder encoder = new DataBufferEncoder();
+
+	@Test
+	public void canEncode() {
+		assertTrue(this.encoder.canEncode(ResolvableType.forClass(DataBuffer.class),
+				MimeTypeUtils.TEXT_PLAIN));
+		assertFalse(this.encoder.canEncode(ResolvableType.forClass(Integer.class),
+				MimeTypeUtils.TEXT_PLAIN));
+		assertTrue(this.encoder.canEncode(ResolvableType.forClass(DataBuffer.class),
+				MimeTypeUtils.APPLICATION_JSON));
+	}
+
+	@Test
+	public void encode() {
+		DataBuffer fooBuffer = stringBuffer("foo");
+		DataBuffer barBuffer = stringBuffer("bar");
+		Flux<DataBuffer> source = Flux.just(fooBuffer, barBuffer);
+
+		Flux<DataBuffer> output = this.encoder.encode(source, this.bufferFactory,
+				ResolvableType.forClassWithGenerics(Publisher.class, ByteBuffer.class),
+				null, Collections.emptyMap());
+
+		assertSame(source, output);
+	}
+
+}

spring-web-reactive/src/main/java/org/springframework/web/reactive/config/WebReactiveConfigurationSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,6 +34,8 @@ import org.springframework.core.codec.ByteArrayEncoder;
 import org.springframework.core.codec.ByteBufferDecoder;
 import org.springframework.core.codec.ByteBufferEncoder;
 import org.springframework.core.codec.CharSequenceEncoder;
+import org.springframework.core.codec.DataBufferDecoder;
+import org.springframework.core.codec.DataBufferEncoder;
 import org.springframework.core.codec.Encoder;
 import org.springframework.core.codec.ResourceDecoder;
 import org.springframework.core.codec.StringDecoder;
@@ -328,6 +330,7 @@ public class WebReactiveConfigurationSupport implements ApplicationContextAware
 	protected final void addDefaultHttpMessageReaders(List<HttpMessageReader<?>> readers) {
 		readers.add(new DecoderHttpMessageReader<>(new ByteArrayDecoder()));
 		readers.add(new DecoderHttpMessageReader<>(new ByteBufferDecoder()));
+		readers.add(new DecoderHttpMessageReader<>(new DataBufferDecoder()));
 		readers.add(new DecoderHttpMessageReader<>(new StringDecoder()));
 		readers.add(new DecoderHttpMessageReader<>(new ResourceDecoder()));
 		if (jaxb2Present) {
@@ -476,6 +479,7 @@ public class WebReactiveConfigurationSupport implements ApplicationContextAware
 		List<Encoder<?>> sseDataEncoders = new ArrayList<>();
 		writers.add(new EncoderHttpMessageWriter<>(new ByteArrayEncoder()));
 		writers.add(new EncoderHttpMessageWriter<>(new ByteBufferEncoder()));
+		writers.add(new EncoderHttpMessageWriter<>(new DataBufferEncoder()));
 		writers.add(new EncoderHttpMessageWriter<>(new CharSequenceEncoder()));
 		writers.add(new ResourceHttpMessageWriter());
 		if (jaxb2Present) {

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,6 +37,7 @@ import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.core.codec.ByteArrayDecoder;
 import org.springframework.core.codec.ByteBufferDecoder;
+import org.springframework.core.codec.DataBufferDecoder;
 import org.springframework.core.codec.StringDecoder;
 import org.springframework.http.codec.DecoderHttpMessageReader;
 import org.springframework.http.codec.HttpMessageReader;
@@ -96,6 +97,7 @@ public class RequestMappingHandlerAdapter implements HandlerAdapter, BeanFactory
 	public RequestMappingHandlerAdapter() {
 		this.messageReaders.add(new DecoderHttpMessageReader<>(new ByteArrayDecoder()));
 		this.messageReaders.add(new DecoderHttpMessageReader<>(new ByteBufferDecoder()));
+		this.messageReaders.add(new DecoderHttpMessageReader<>(new DataBufferDecoder()));
 		this.messageReaders.add(new DecoderHttpMessageReader<>(new StringDecoder()));
 	}
 

spring-web-reactive/src/test/java/org/springframework/web/reactive/config/DelegatingWebReactiveConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,8 +37,13 @@ import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
 import org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
-import static org.mockito.BDDMockito.*;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.BDDMockito.any;
+import static org.mockito.BDDMockito.doAnswer;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.BDDMockito.verify;
 
 /**
  * Test fixture for {@link DelegatingWebReactiveConfiguration} tests.
@@ -99,7 +104,7 @@ public class DelegatingWebReactiveConfigurationTests {
 		verify(webReactiveConfigurer).addArgumentResolvers(any());
 
 		assertSame(formatterRegistry.getValue(), initializerConversionService);
-		assertEquals(6, readers.getValue().size());
+		assertEquals(7, readers.getValue().size());
 	}
 
 	@Test

spring-web-reactive/src/test/java/org/springframework/web/reactive/config/WebReactiveConfigurationSupportTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -139,7 +139,7 @@ public class WebReactiveConfigurationSupportTests {
 		assertNotNull(adapter);
 
 		List<HttpMessageReader<?>> readers = adapter.getMessageReaders();
-		assertEquals(6, readers.size());
+		assertEquals(7, readers.size());
 
 		assertHasMessageReader(readers, byte[].class, APPLICATION_OCTET_STREAM);
 		assertHasMessageReader(readers, ByteBuffer.class, APPLICATION_OCTET_STREAM);
@@ -189,7 +189,7 @@ public class WebReactiveConfigurationSupportTests {
 		assertEquals(0, handler.getOrder());
 
 		List<HttpMessageWriter<?>> writers = handler.getMessageWriters();
-		assertEquals(7, writers.size());
+		assertEquals(8, writers.size());
 
 		assertHasMessageWriter(writers, byte[].class, APPLICATION_OCTET_STREAM);
 		assertHasMessageWriter(writers, ByteBuffer.class, APPLICATION_OCTET_STREAM);
@@ -215,7 +215,7 @@ public class WebReactiveConfigurationSupportTests {
 		assertEquals(100, handler.getOrder());
 
 		List<HttpMessageWriter<?>> writers = handler.getMessageWriters();
-		assertEquals(7, writers.size());
+		assertEquals(8, writers.size());
 
 		assertHasMessageWriter(writers, byte[].class, APPLICATION_OCTET_STREAM);
 		assertHasMessageWriter(writers, ByteBuffer.class, APPLICATION_OCTET_STREAM);